Polychlorinated cyclic hydrocarbons have been known for many years as good insectcides and many of them have been widely used in the past. Such insecticides as DDT, dieldrin, endrin, chlordane, lindane, heptaclor, aldrin, and toxaphene are examples. As the use of these compounds became more widespread and continued for several years, evidence mounted that these compounds were extremely stable to biodegradation and were found to be accumulating in the tissues of animals, birds and fishes, and therefore presumably in man, with toxic effects. As a result, the use of these obviously good insecticides has fallen into disfavor and actually has been banned in many instances. The need for strong pesticides which are not toxic to animals and do not bioaccumulate in the fat and tissues of animals is quite evident and has attracted much attention among researchers, but with very little success.